Shaft power plant

ABSTRACT

A shaft power plant ( 1 ) for generating electricity by energy conversion of a discharge between a headwater ( 2 ) and a tailwater ( 6 ), comprising a vertical shaft ( 7 ), the top ( 10 ) of which forms an inflow plane ( 11 ) which is parallel to the bed and extends below the water level ( 3 ) of the headwater, wherein the shaft ( 7 ) is open toward the top and is closed by a base ( 9 ) at its bottom end, a unit ( 15 ) composed of a turbine ( 16 ) and an electrical machine ( 17 ), wherein the unit ( 15 ) is arranged entirely under water in the shaft ( 7 ) and wherein the turbine ( 16 ) is arranged for water to pass through horizontally, and an outflow ( 24 ), which is connected to the turbine ( 16 ), represents a closed flow channel and leads through a through-passage ( 28 ) in the shaft ( 7 ) to the tailwater ( 6 ), wherein a horizontal first cross-sectional area of the shaft ( 7 ) is much larger than a vertical second cross-sectional area taken up by the turbine runner ( 19 ).

The invention relates to a shaft power plant and also to a shaft powerplant module for generating electricity by energy conversion of adischarge between a headwater and a tailwater. To this end, theinvention discloses a much simpler inflow concept for hydropower plantson damming structures, wherein all the important hydro-engineeringrequirements with regard to hydraulics, silt accretions, bed-loaddischarge, high water capability and also the necessary ecologicalcomponents are taken into account.

On account of necessary climate protection, the continually increasingprices in the energy sector and further environmental effects, there arefor the first time serious political commitments to sustainable energyconcepts in Germany and also around the world. As a result of thepositive development in the expansion of renewable energies, the GermanFederal Ministry for the Environment (Bundesministerium für Umwelt—BMU),in its 2007 progress report on the Renewable Energy Act(Erneuerbare-Energien-Gesetz—EEG), set a new expansion target of atleast 27% electricity provision from renewable sources by the year 2020and at least 45% by the year 2030. However, the BMU report alsocriticized the fact that the expansion of hydropower had hithertoremained far behind expectations. Causes for the stagnation in theexpansion of hydropower in Germany were both the lack of economicincentives and also the high ecological requirements involvingprotracted and expensive authorization procedures. In addition, therewas and is the risk of having to accept an application rejection, sinceevaluations are frequently made with nature conservation predominant andwithout objective assessment.

The fact that the BMU desires a further increase at all in electricitygeneration by hydropower, which is criticized by environmentalorganizations, can probably also be due to the fact that this manner ofproducing electricity is back in high regard on account of manyenvironmentally relevant properties—high energy returned on energyinvested, external CO₂ costs, constant availability, relativelyfavorable production costs—and this has also been rewarded since January2009 with increased rates of remuneration.

In Germany, a further expansion of hydropower is regulated by theprovisions in the BMU's Guideline for the remuneration of electricityfrom hydropower and also by the exist in principle only for locationshaving existing transverse structures and simultaneous ecologicalimprovement.

In reinforced-bed fluvial topographies, the basic water level must beprotected, and so a local gradient jump must be retained even fromecological and economic points of view—ramp structures are expensive,are hydraulically inefficient for high water discharge and have a poorCO₂ balance. The poor CO₂ balance of ramp structures results from thequarrying and truck transportation of very large quantities of hardrock. This provides essential preconditions for hydropower utilization.When an ability to pass through is provided at the same time, theprovisions according to the EEG guideline of the BMU must also be met.The construction of relatively large or large plants in Germanycontinues to be restricted thereby or is made more difficult orprevented.

On account of the established boundary conditions (EEG remuneration,defined requirements), the interest in new hydropower plants hasincreased considerably, in spite of site conditions that are not ideal.However, practice has frequently shown that economic efficiency canscarcely be ensured with conventional power plant technology, in spiteof better remuneration, in particular with a decreasing drop height, andit could even be possible for stagnation to occur again. However, ifthere is a desire to generate more electricity from hydropower, evenwith less favorable conditions, because of its convincingenvironmentally positive properties, new technical components having anecological orientation are required for more efficient use.

The benefit of promoting new, practical developments in this sector isadditionally enhanced because more efficient hydropower concepts can beinstalled around the world.

Small-scale hydropower provides particular advantages for emerging anddeveloping nations because, for example, with small drop heights onlysimple structural requirements are set for the damming structure, noreservoir banks are necessary and only marginal changes have to be madeto the watercourse. Since, as a rule, the generation of electricity fromrun-of-the-river hydropower plants is largely ensured at least withpartial load and occurs in a highly predictable manner, an importantdemand for supply reliability can be fulfilled even in decentralizedsettlement structures in isolated operation.

The technology for generating electricity from hydropower is inprinciple fully developed for larger plants, as is clearly documented bythe extremely high overall efficiency of up to 90%. Even in partial loadoperation, excellent conversion into electrical energy can take place invirtually all types of turbine.

On account of the demand for renewable sources of electricity, in thelast few years, more intensive research has been carried out in thefield of small-scale and very small-scale hydropower. In addition toincreases in efficiency and technological improvements in water wheels,a number of new types of turbine have been developed, these new types ofturbine taking account to some extent of the issues of downstream fishmigration and the passage of fish. Particularly noteworthy are in thiscase the technologies of matrix turbines and hydropower screws. Bothtypes have in the meantime achieved a certain market maturity.

In summary, it can be established that improved types of turbine havebeen developed in niche segments. However, for the sites of interesthaving the defined boundary conditions according to the BMU guideline,it is not the type of turbine that is decisive but the efficiency of theentire plant concept, in which the particular hydraulic-engineeringconditions of fixed, usually silted-up weir systems should be taken intoaccount. An essential demand consists additionally in the ability thatis to be created to pass through upstream and downstream, wherein harmto fish caused by turbines should be avoided.

Hydropower utilization for the relevant sites in Germany usually takesplace in the conventional form of a bay-type power plant having highstructural outlay and to some extent considerable encroachment in thebanks. If no increases in the water level are allowed to be carried out,extremely unfavorable preconditions occur for the incident flow of thepower plant on account of the low flow depths, and these preconditionscan be circumvented to a limited extent only by deepening the inflows,which is associated with technical, operational and also economicdisadvantages.

Since a virtually vertical screen plane arranged at a low level isspecified, even in the case of bed-load discharge, extensive deepeningof the bed has to be carried out in order that minimum hydraulicrequirements for the flow conditions can be ensured. For this purpose,upstream basins for bed-load deposition and flushing sluices forbed-load transmission should be arranged in the upper inward flowregion. The inflow structure must be designed and dimensioned such thatthe natural, wide flow cross section is diverted with as little loss aspossible into the compact bay cross section. Operational analyses thathave been carried out show that in operational bay-type power plantsapproximately 2/3 of the costs have to be estimated for the structuralproportion.

Disadvantages of previously known bay-type power plants in overview:extensive flow diversion, extensive encroachment in the banks, extensivedeepening of the bed, which has to be protected by a bed-load sluice,noise pollution, to some extent negative visual effect on account ofpower plant buildings and ecological impairment of the previous stretchof river between inlet and outlet with downstream fish migration whichis difficult to achieve.

It is the object of the invention to provide a hydropower plant whichcan be operated in an environmentally sound and efficient manner whilebeing cost-effective to produce.

The object is achieved by the features of the independent claims.Advantageous developments are the subject matter of the dependentclaims.

In order to be able to achieve increases in efficiency, a fundamentalchange in the plant design is necessary. The invention set out in thefollowing text involves essentially a change from the vertical inflowplane to the horizontal inflow plane by means of a vertical shaft, fromwhich considerable hydraulic, ecological and economic advantages can bederived. The invention involves an underwater hydropower concept,preferably at damming structures. In this case, damming structuresshould be understood as meaning in particular river barriers, dams,check dams, dam walls, weir systems, historic and also landmarked weirsystems, transverse structures, locks, plants regulated by dams and/orthe damming of flowing or standing waters. Furthermore, the expressiondamming structure relates here to a natural barrier between a headwaterand a tailwater. All important hydraulic-engineering requirements withregard to hydraulics, silt accretions, bed-load discharge, high watercapability and also the necessary ecological components are taken intoaccount according to the invention.

Thus, the invention is achieved by a shaft power plant for generatingelectricity by energy conversion of a discharge between a headwater anda tailwater, comprising a vertical shaft, the top of which forms aninflow plane which is parallel to the bed and extends below the waterlevel of the headwater, wherein the shaft is open toward the top and isclosed by a base at its bottom end, a unit composed of a turbine and anelectrical machine, wherein the unit is arranged entirely under water inthe shaft and wherein the turbine is arranged for water to pass throughhorizontally, and an outflow, which is connected to the turbine,represents a closed flow channel and leads through a through-passage inthe shaft to the tailwater, wherein a horizontal first cross-sectionalarea of the shaft is much larger than a vertical second cross-sectionalarea taken up by the turbine runner.

Preferably, the entire unit is in contact with water on all sides so asto ensure sufficient cooling.

Preferably, the turbine can also be arranged in an oblique manner, i.e.the turbine axis is at any desired angle between the horizontal and thevertical. Preferably, a deviation of the angle of the turbine axis fromthe horizontal of up to +/−40°, in particular up to +/−25°, inparticular up to +/−15°, is defined as an arrangement “for water to passthrough horizontally”. More preferably, a deviation of the angle of theturbine axis from the vertical of up to +/−40°, in particular up to+/−25°, in particular up to +/−15°, is defined as an arrangement “forwater to pass through vertically”.

The arrangement for water to pass through horizontally is suitable inparticular for very low drop heights. In this case, it is perfectlypossible for a water level of the tailwater to be at the same level asthe headwater bed plane. Furthermore, overall depth can be saved in thecase of small drop heights, thereby entailing considerable costadvantages.

Preferably, the first cross-sectional area is defined at the level of aturbine axis of the turbine or at the level of the shaft top. If thefirst cross-sectional area is located at the level of the turbine axis,it is measured with the unit composed of the turbine and the electricalmachine being disregarded. If the first cross-sectional area is locatedat the level of the shaft top, it is measured with any screenarrangements being disregarded. In other words, the firstcross-sectional area is, for example in the case of a rectangular shaft,the product of the two clear side lengths of the shaft, wherein, in thecase of vertical shaft walls, the first cross-sectional area isidentical at the turbine axis and at the shaft top. The secondcross-sectional area corresponds to a flow cross section in the turbinechannel and is specified for example by the product of half the diameterof the turbine runner squared and pi. In a preferred configuration, itis provided that the first cross-sectional area is at least 1.5 times,in particular 5 times, in particular 10 times, in particular 30 timeslarger than the second cross-sectional area.

The definition “inflow plane which is parallel to the bed” also includesan inflow plane which is inclined slightly, in particular up to +/−40°,in particular up to +/−20°, in particular up to +/−10°, in particular upto +/−5°, with respect to the bed plane. The bed plane can deviate fromthe horizontal in particular in check dams. In the case of torrents, thenegative inclination in particular is recommended, in particular up to−40°. In the case of the negative inclination, the inflow plane isinclined in the direction of the tailwater.

The unit is characterized by a compact construction, preferably having apermanent magnet synchronous generator having a variable speed and/or adirect coupling between the turbine and the electrical machine and/orvirtually maintenance-free underwater operation. As a result of theseproperties, there is no need for a power house building and only theelectronics needs to be set up in a container or building away from thewater. On account of the specific construction of the turbine which isflowed through horizontally, a fundamental change in the inflow planeand screen plane can be carried out.

The shaft power plant according to the invention enables morecost-effective hydropower utilization on flowing waters havingtransverse structures in order to generate different energy levels inthe body of water. Typical examples of such sites of application are,inter alia, existing transverse structures and historic weirs. Theconcept can also be applied at other sites, for example at check dams orin medium pressure systems which are silted-up or at risk of silting up,and also in artificial lakes and reservoirs.

The potential of such sites is also present in Germany and can beimplemented economically on account of the optical advantages and lowconstruction costs. As a result of the simple arrangement, therobustness and low maintenance requirement, the relatively lowconstruction outlay and the possibility of working in a modular mannerwith prefabricated elements, use outside Germany and Europe, around theworld, in particular also in developing nations, is possible.

With the concept of the shaft inflow, on account of the horizontalarrangement, the frequently required quotient ofQ_(turbine)/A_(screen area)<0.5 m/s can be achieved much more easily andcost-effectively, because the shaft cross section has to be increasedonly two-dimensionally and furthermore no areas of the banks are takenup. Previously known bay-type power plants often achieve only Q/A=1 m/s.Q is the discharge in the turbine in m³/s. A denotes the shaftcross-sectional area in the screen plane. In order to protect fish, theshaft cross-sectional area in the screen plane has to be selected to belarge enough for the fish to be able to perceive the barrier and toreact and to be able to escape under their own power, and for theirphysical capabilities to escape not to be exceeded, in other words, inextreme cases, Q_(turbine)/A_(screen area)<0.3 m/s should be preferred.

It is further preferred for the shaft top, or inflow plane, to extend inthe bottom half, in particular in the bottom third, of a water depth ofthe headwater.

Advantageously, the shaft is open over its entire top side, with theexception of any screens. It is also advantageous for all of the sidewalls of the shaft to extend vertically, so that the firstcross-sectional area is constant over the entire shaft depth. As aresult, any restriction in the incident flow is prevented and the shaftcan be produced very simply. The expression “vertical” side walls alsoincludes a slight inclination, in particular up to +/−30°, in particularup to +/−10°, in particular up to +/−5°, with respect to the shaft base.It is also preferred for the shaft to be configured with deflectingwalls that extend in a flow-favorable manner.

In a preferred configuration, the turbine, in particular the turbinerunner, is arranged below the bed plane of the headwater and/or isarranged in the bottom half, in particular in the bottom third, of theshaft. The turbine and the electrical machine are preferably arrangedclearly below the shaft top. In high channel flows, bed-load can passinto the shaft, the bed-load is flushed over the shaft by the positionedflap, i.e. the height of the shaft with regard to the river bed and theposition of the turbine wheel below the inflow edge that holds back thebed-load are important.

It is advantageous for the turbine axis (rotational axis) of the turbinerunner and an armature axis of the electrical machine to be arrangedcoaxially with one another and horizontally. Furthermore, it ispreferably provided that the outflow widens, in particular continuously,directly after the turbine. It is particularly preferred for the outflowto comprise, in the following order downstream of the turbine, a flaringcone and a suction pipe or a suction hose.

The suction pipe or suction hose are configured preferably as a diffuserfor recovering the velocity energy.

Preferably, the base of the shaft is arranged below the bed plane of theheadwater. The shaft thus extends as far as below the bed plane of theheadwater.

Preferably, the outflow extends through a side wall of the shaft to thetailwater. The unit is preferably mounted directly on the shaft wall.

In a further advantageous configuration, the inflow into the shaft isprovided with a horizontal screen plane, which corresponds to thehorizontal inflow plane, or a vertical screen plane having in particulara horizontal cover over the shaft. Preferably, use is made of anupstream coarse screen and a downstream fine screen. The fine screen isconfigured preferably with a grating spacing of <20 mm. Preferably, bothscreens have rotatable screen bars and/or a mechanical cover, e.g. arolling cover, and also a screen cleaning device under water.

Preferably, the shaft power plant comprises a damming structure betweenthe headwater and the tailwater. In this case, damming structures shouldbe understood as meaning in particular river barriers, dams, check dams,dam walls, weir systems, historic and also landmarked weir systems,transverse structures, locks, plants regulated by dams and/or thedamming of flowing or standing waters. Furthermore, the expressiondamming structure relates here to a natural barrier between a headwaterand a tailwater.

Preferably, a flap which is permanently overflowed is arranged in thedamming structure, in particular over the entire inflow width.Preferably, the shaft is configured with a polygonal or semicircularcross section, wherein one longitudinal side butts directly against thedamming structure. Further preferably, the flap can be pivoted about ahorizontal axis to enlarge the overflow and simultaneously to open anunderflow. As an alternative to the pivotable flap, a rotary flap ispreferred, wherein the rotary flap comprises on its bottom edge anintegrated closure which allows the underflow to be regulated dependingon the overflow.

The headwater level is regulated up to the maximum normal discharge ofthe turbine by the vane position of the preferred guide apparatus andthe speed of the turbine runner. On account of the compact structuralform with forced vertical diversion of the works water, a pronouncededdy formation is produced at the transition from free flow discharge topressurized discharge. As was shown by the experiment on the physicalmodel, even a relatively small, wide flap overflow prevents rotary flowwith eddy formation that draws in air.

By way of the flap arranged on the end side, four essential effects areachieved: Prevention of eddy formation in the inflow by permanentoverflow with simultaneous oxygen regulation. In this case, it ispossible to regulate both the introduction and the removal of oxygen inthe case of oversaturation. Wide and direct surface outflow into thetailwater. Eels, which live close to the bottom and only swim downstreamon a few days in the fall could be allowed to pass into the tailwaterwithout being harmed by temporarily opening the integrated cleaningclosure, which is flush with the bed, or, if a pivoting flap isinstalled, by rotating the latter. Removal of driftwood and floatingdebris via the flap and removal of the screening material under theflap. And also, if appropriate, control of the headwater level.

On account of the permanent overflow of the flap, laminar flow close tothe surface develops in the entire inflow region, as a result of whichfish which particularly wish to migrate, in particular young fish thatlive predominantly at the surface, can descend without being harmed.

In order to meet the preferred requirements, a rotary flap must beequipped with a low, integrated closure. The alternative pivoting flaphas a centrally arranged pivot pin, as a result of which a rotationalmovement in the clockwise direction simultaneously ensures or increasesthe under- or overflow. In order to be able to open the entire surfacecross section in high channel flows and not to cause the risk of a logjam, use is preferably made of technology which allows the central pivotpin to be uncoupled and a pin at the bottom of the flap to be inserted.

Preferably, a bottom edge of the flap is arranged at the level of theshaft top.

Alternatively, it is advantageous for a flushing channel, which islocated lower than the shaft top and lower than the bed plane of theheadwater, to extend around the shaft, wherein the flushing channelleads to the flap and the bottom edge of the flap is arranged at thelevel of the flushing channel. The flap is preferably provided with aregulating device which is suitable for producing a bed-load dischargingflushing surge.

Bed-load discharge takes place in the case of larger channel flows,wherein complete silting up can occur very frequently up to the shafttop in fixed weir systems. On account of the relatively small coverage,the flap flushing system according to the invention is effective. Inconventional plants, complicated and extensive flushing structures arerequired on account of the subterranean development. By way of finescreening, the introduction of coarse bed-load is prevented, sands causevirtually no damage to the turbine in the low-pressure range.

Bed-load discharge and driftwood transport usually take place in highchannel flows. In order to avoid corresponding mechanical and structuraldamage, the screen bars can preferably be designed in a rotatable manner(use as closure plane) in order to prevent the introduction of bed-loadand floating matter into the shaft. At the same time, in the case ofhigher channel flows, the flap closure is designed with the effect thata drawdown curve forms over the screen plane and sufficiently largeentraining forces are generated thereby to keep the inflow region freeof bed-load. The shaft and flap should be dimensioned for the requiredfull-area flushing action.

In conventional inflows, fish migrating downstream can be pushed againstthe inflow screen at high flow rates or get into the turbines ofhydropower plants, as a result of which they risk being harmed. With thetechnical corrective measures carried out hitherto, it was possible toachieve at best partial successes. Thus, bypass systems for downstreamfish migration are often without effect and constructive turbinesolutions (runner geometry, speed) are associated with considerablelosses of efficiency, with the question of the actual reduction in harmremaining open. According to the invention, a considerable reduction inharm to the fish stock is possible on account of the creation of safemigration corridors into the tailwater and the lowering of the incidentflow speeds in the screen plane to preferably v_(m)<0.5 m/s. In order tomeet just the requirements for low incident flow speeds, in conventionalpower plant inflows having a vertical plane, the structures would haveto be considerably increased in size, since hitherto dimensioning wascarried out with v_(m screen)≦1.0 m/s.

With the concept of the shaft inflow according to the invention, onaccount of the horizontal arrangement, the required large screen surfacecan be produced with moderate flow rates without expensive rampstructures. The second requirement for functional migration corridorsremains largely unmet in conventional power plants. With the shaftconcept according to the invention, on account of the flap arrangementhaving the hydraulically necessary permanent overflow, there is thepossibility, by preferably triangular or semicircular indentation in thetop region of the flap, of reinforcing the direct outflow such that itis used by fish which wish to migrate. Eels, which live close to thebottom and only swim downstream on a few days in the fall, could beallowed to pass into the tailwater without being harmed by temporarilyopening the integrated cleaning closure, which is flush with the bed, onthe bottom edge of the flap. The proposed downstream fish migrationtechniques are promising because, in addition to the low flow rates inthe fine screen plane, there is a short and direct path to the wide flapoverflow or underflow. Preference is given to both continuous and(sensor) controlled operation, in which particular consideration couldbe given to the time periods for downstream fish migration.

On account of the preferred direct positioning of the shaft according tothe invention at the weir body or damming structure, and also the fullyunderwater arrangement, further positive effects are achieved:completely invisible power plant buildings, retention of the waterway inthe river bed without serious flow diversions and impairment of theecological fauna and ecological flora, no formation of dead zones in thetailwater, and avoidance of noise pollution on account of the fullyunderwater arrangement.

Also preferred are adjustable screen bars as a closure device and/orother motorized covers and/or underwater screen cleaners and/or anintegrated closure part, necessary for the transmission of the screeningmaterial, on the bottom edge of the flap.

As an alternative to the recessed arrangement of the shaft in the bed,it is preferably provided that the base of the shaft is arranged abovethe bed plane of the headwater.

Preferably, to this end, the shaft is supported on the bed and/orfastened to the damming structure, in particular suspended, and/orarranged in a manner standing on a protrusion from the dammingstructure. Particularly preferably, the outflow comprises a cylindricalthroughflow of constant cross section, in particular configured as aborehole, through the damming structure. The cylindrical section isadjoined preferably by a cross-sectional widening, in particular adiffuser, as the transition to the tailwater.

This variant is used preferably in medium pressure plants or inconventional dams. The shaft height on the damming structure is selectedin a manner depending on the height of the dam and the silting scenario.The recovery of energy in the diffuser takes place preferably only onthe air side.

As an alternative to the direct attachment of the shaft to the dammingstructure, the shaft is set up on the bank or bored directly into therock or constructed in the rock. In this case, an existing diversion cutcan be used in a modified manner as a connection to the tailwater. Theshaft is configured preferably as a cylindrical borehole, in particularin the rock. In the case of stable rock, the walls of the borehole, thatis to say the rock itself, forms the shaft wall directly. Alternatively,the shaft can be inserted into the borehole or be concreted in theborehole. Provision is furthermore advantageously made of an inward flowfrom the headwater into the shaft or into the borehole by means of adiversion. Two variants of a shaft in the rock are preferred. In thefirst variant, the lake contents (headwater) are turbined into thetailwater via a shaft in the rock. In the second variant, diversions areturbined into the lake. Diversions guide the water in the free flowdischarge from a different valley into a pool. This means that there isalways a difference in level between the arriving free flow dischargeand the water level in the pool. This difference, which is reduced asthe pool fills, can preferably be used energetically. In previouslyknown methods, this difference is not used and the water runs over therocks into the reservoir.

An overview of the advantages of the shaft power plant according to theinvention: marginal flow diversion on account of the preferred modularconstruction and preferred multiple arrangement of a plurality of shaftpower plants at a damming structure, turbines can be integrated in andon the weir without serious flow diversion, shaft inflow with ahorizontal screen plane, little deepening of the bed by way of end-sideflap flushing, no structural encroachments on the banks, no noisepollution, no generator cooling necessary, no visible power plantbuildings, downstream fish migration possible via continuously chargedflushing flap.

The invention furthermore comprises a shaft power plant module forgenerating electricity by energy conversion of a discharge between aheadwater and a tailwater, comprising a vertical shaft module, the shafttop of which forms an inflow plane which is parallel to the bed and isconfigured to extend below the water level of the headwater, wherein theshaft module is open toward the top and is closed by a base at itsbottom end, a unit module composed of a turbine and an electricalmachine, wherein the unit module is configured to be arranged entirelyunder water in the shaft module and wherein the turbine is configured tobe arranged for water to pass through horizontally, and an outflowmodule, which is connected to the turbine, represents a closed flowchannel and is configured to lead through a through-passage in the shaftmodule to the tailwater, wherein a horizontal first cross-sectional areaof the shaft module is much larger than a vertical secondcross-sectional area taken up by the turbine runner.

The advantageous configurations, as have been discussed in connectionwith the shaft power plant according to the invention, are preferablyapplied in a corresponding manner to the shaft power plant moduleaccording to the invention. The separate shaft module, which can also beset up independently of a damming structure, comprises a shaft which isflowed through and has a vertical inflow plane, and a turbine having anelectrical machine, these being arranged permanently under water. Theshaft module can preferably be set up freely in a naturally orartificially dammed body of water or be built onto (hydraulic)structures having different functions. The shaft module integratespreferably a horizontal screen plane having a cleaning means. Eddiesmust be prevented by means of hydraulic measures. The modularconstruction allows the shaft power plant to be set up in a mannerlocally detached from (e.g. upstream of) a damming structure to beerected, an already existing dam or in an existing water pool. Ahydraulic connection between the headwater and the tailwater must beensured in each case.

The shaft power plant or shaft power plant module according to theinvention comprises preferably a shaft having a simple cross section, inparticular rectangular or circular or semicircular, having vertical oralmost vertical walls. In any case, the usual flow-favorableconstriction toward the turbine is preferably avoided and thus acost-effective shaft geometry is selected. For flow diversion, simpleguide elements or an optimized guide apparatus of the hydraulic machinecan preferably be used. Guide elements formed in a flow-favorablemanner, in particular guide elements that extend in a spiral shape arepreferably arranged in the shaft. The cross section of the shaft ispreferably much larger than that taken up by the turbine runner. Inpreviously known equipment, the different cross sections are compensatedby a complex, curved shell, in order to keep losses low. By contrast, inthis case preferably a hydraulically unfavorable geometry is selected,with the unfavorable flow path being offset by a large cross-sectionalarea and possibly by guide elements and/or guide apparatus. The speedsare low on account of the large cross-sectional area and the hydrauliclosses are correspondingly also low.

Preferably, in the proposed power plant, use is not made of an airspace, a means of access or a lateral connection in the form of aconventional, accessible power plant control center. In previously knownequipment, the turbines are set up in a dry, cohesive space,specifically alongside one another, i.e. one turbine per inflow.According to the invention, there is no such transverse connection.

The invention is explained in more detail in the following text on thebasis of exemplary embodiments, in which:

FIG. 1 shows a section through a shaft power plant according to theinvention according to a first exemplary embodiment,

FIG. 2 shows a further section through the shaft power plant accordingto the invention according to the first exemplary embodiment,

FIG. 3 shows a plan view of the shaft power plant according to theinvention according to the first exemplary embodiment,

FIG. 4 shows a sectional view of the shaft power plant according to theinvention according to a second exemplary embodiment,

FIG. 5 shows a further sectional view of the shaft power plant accordingto the invention according to the second exemplary embodiment,

FIG. 6 shows a plan view of the shaft power plant according to theinvention according to the second exemplary embodiment,

FIG. 7 shows a sectional view of the shaft power plant according to theinvention according to a third exemplary embodiment,

FIG. 8 shows a further sectional view of the shaft power plant accordingto the invention according to the third exemplary embodiment,

FIG. 9 shows a plan view of the shaft power plant according to theinvention according to the third exemplary embodiment,

FIG. 10 shows a first variant of a flap for all three exemplaryembodiments, and

FIGS. 11 and 12 show a second variant of the flap for all threeexemplary embodiments.

In the following text, three exemplary embodiments of a shaft powerplant 1 according to the invention are explained in detail.

FIGS. 1 to 3 show the first exemplary embodiment of the shaft powerplant 1. In this case, a headwater 2 having a headwater level 3 and aheadwater bed plane 4 can be seen. Between the headwater level 3 and theheadwater bed plane 4 there extends a headwater depth 5. Locatedsomewhat lower than the headwater 2 is a tailwater 6. The shaft powerplant 1 utilizes the drop height between the headwater 2 and thetailwater 6 to generate electrical energy.

To this end, the shaft power plant 1 comprises a vertical shaft 7comprising vertical side walls 8 and a base 9. The base 9 of thevertical shaft 7 is arranged horizontally. The side walls 8 extendvertically upward from this base 9. The side walls 8 terminate level andflush with a shaft top edge or shaft top 10. This shaft top 10 defines ahorizontal inflow plane 11 of the shaft 7. A clear shaft depth 34 isdefined from this horizontal inflow plane 11 as far as the top edge ofthe base 9. The horizontal inflow plane 11 is located clearly below theheadwater level 3 and is higher than the headwater bed plane 4 by aprotrusion 33.

Located on the side wall 8 of the shaft 7 there is a horizontallyarranged unit comprising a turbine 16 having a turbine axis 45, anelectrical machine 17 in the form of a generator, and a guide apparatus18. The turbine 16 is in this case connected firmly to the side wall 8.Located directly next to the turbine 16 is the guide apparatus 18 andlocated directly next to the guide apparatus 18 is the electricalmachine 17. An essential component of the turbine 16 is a verticallyarranged turbine runner 19 having a turbine runner diameter 20. Arotational axis (turbine axis 45) of the turbine runner 19 and also anarmature axis of the electrical machine are coaxial with one another andhorizontal.

The upwardly open side of the shaft 7 is provided with a horizontallyarranged screen 21. This screen 21 is located in the horizontal inflowplane 11. Furthermore, in order to clean the screen 21, a screencleaning means 22 is arranged within the shaft under water. Extendingone side wall 8 of the shaft 7 there is a flap 23, which enables aconnection between the headwater 2 and the tailwater 6, bypassing theshaft 7 and in particular bypassing the unit 15. The flap 23 isdescribed in detail in FIGS. 10 to 12.

The unit 15 fastened to the side wall 8 is located directly at acircular through-passage 28 in the side wall 8. As a result, the unit 15can be connected to the tailwater 6 via an outflow 24 forming a flowchannel. To this end, the outflow 24 comprises a cone 25, which isadjoined by a suction pipe or suction hose 27. The cone 25 is insertedin the through-passage 28 and is connected in a sealed manner to anoutlet from the turbine 16. Via this cone 25, the flow runs directlyinto the suction hose 27.

FIGS. 2 and 3 likewise show the first exemplary embodiment. Indicated inthe plan view according to FIG. 3 is a section A, as is shown in FIG. 1,and a section B as per FIG. 2. It can be clearly seen in FIGS. 2 and 3that one vertical side wall 8 of the shaft 7 directly adjoins a dammingstructure 30. FIG. 3 shows a horizontal cross-sectional area of theshaft 7 (first cross-sectional area), said cross-sectional area beingdefined by a first clear side length 31 and a second clear side length32 of the shaft 7. The cross-sectional area of the shaft 7 is thus theproduct of the first side length 31 and the second side length 32. Apartfrom a small narrowing of the shaft 7 by a shoulder below a flap 23, thefirst cross-sectional area at the level of the shaft top 10 and at thelevel of the turbine axis 45 is identical here. A verticalcross-sectional area (second cross-sectional area) taken up by theturbine runner 19 is calculated from the turbine runner diameter 20indicated in FIG. 1. The cross-sectional area taken up by the turbinerunner 19 within the turbine 16 is thus the product of half the turbinerunner diameter 20 squared and pi. What is decisive in the presentinvention is, then, that the cross-sectional area of the shaft 7 is muchlarger than the cross-sectional area taken up by the turbine runner 19.As a result, the flow rate of the water in the screen plane is very lowand is accelerated only just before the turbine 16, as a result of whichthe loading of the shaft 7 with entrained and floating material isreduced and also fish can pass the shaft power plant 1 via the flap 23without passing through the turbine passage.

The water flows into the shaft 7 from three sides via the horizontalinflow plane 11 in the inflow direction 29 indicated in FIGS. 1, 2 and3. By way of the guide apparatus 18, the water is guided horizontally tothe turbine runner 19. At the turbine outlet, the water flows via thecone 25 and leaves the shaft power plant 1 via the suction hose 27 andflows away into the tailwater 6. The rotational movement of the turbinerunner 19 is converted into electric current via the electrical machine17. In this case, the entire unit 15 is seated in the shaft 7 and thusentirely under water. Consequently, no further cooling of the unit 15 isnecessary. The electric current generated is guided toward the outsideby a cable connection which is not shown.

FIGS. 4, 5 and 6 show a second exemplary embodiment of the shaft powerplant 1. Identical or functionally identical components are describedwith the same reference signs in the second exemplary embodiment as inthe first exemplary embodiment.

In contrast to the first exemplary embodiment, the second exemplaryembodiment shows a variant having a semicircular, vertical shaft 7 andalso a vertically arranged screen 21.

It can be clearly seen in FIGS. 4 and 5 that in this case the screen 21is provided vertically as an extension of the semicircular, verticalside wall 8 of the shaft 7. In this case, the screen 21 extends from theshaft top 10 as far at least as the headwater level 3. For safetyreasons, the entire shaft 7 is covered with a cover 35 approximately atthe level of the headwater level 3.

FIG. 6 shows the semicircular configuration of the vertical shaft 7,with the straight side of the semicircular shaft 7 being combined withthe damming structure 30. This is shown in particular in FIG. 4,according to which the vertical side wall 8 merges integrally into thedamming structure 30 exactly from the horizontal inflow plane 11. Across-sectional area (first cross-sectional area) of the shaft 7 isdefined by the radius 36. Thus, the cross-sectional area of the shaft 7is calculated here from half the product of the radius 36 squared andpi.

In the second exemplary embodiment, two flaps 23 are provided to theside of the shaft 7. The bed-load carried along by the headwater 2 getscaught at the protrusion 34 and slides around the semicircle to theflaps 23. This prevents the turbine 16 from taking in too much bed-load.

FIGS. 7 to 9 show a third exemplary embodiment of the shaft power plant.Identical or functionally identical components are designated by thesame reference signs in the first, second and third exemplaryembodiments.

The third exemplary embodiment is configured in the same way as thesecond exemplary embodiment with a semicircular, vertical shaft 7, twoside flaps 23 and vertically standing screens 21 having horizontal bars.

As an additional feature, in the third exemplary embodiment a flushingchannel 37 is formed around the entire semicircle outside the shaft 7 oroutside the vertical shaft walls 8. This flushing channel 37 leads fromone flap 23, around the shaft 7, to the other flap 23. In this case, theflushing channel 37 is located below the headwater bed plane 4 by aflushing channel depth 38. Thus, in the third exemplary embodiment it isno longer just the protrusion 33 that serves to collect the bed-load butalso the flushing channel depth 38. When the flaps 23 on both sides ofthe shaft 7 are opened, a flushing flow 39 toward the two flaps 23 isproduced in the flushing channel 37.

It should in particular be pointed out that the different properties ofthe three exemplary embodiments can be mixed. Thus, in each of the threeexemplary embodiments, preference is given to both a horizontal and avertical screen arrangement, a round or polygonal shaft geometry, one ormore flaps 23 and/or a flushing channel 27.

In the following text, two different variants of the flap 23 arepresented on the basis of FIGS. 10, 11 and 12. Either of the two flapvariants can be applied advantageously to all three exemplaryembodiments.

FIG. 10 shows a first variant of the flap 23. As was shown in thevarious exemplary embodiments, the flap 23 can be arranged either on aside wall 8 of the vertical shaft 7 or in the damming structure 30. Inthe closed state, as shown in FIG. 10, the flap 23 is offset downwardslightly with respect to the headwater level 3, so that a permanentoverflow 41 is produced. Furthermore, the flap 23 in the first variantis rotatable, so that the overflow 41 can be regulated.

In the lower region of the flap 23, it can be seen that a bottom edge ofthe flap 23 is located approximately at the level of the screen 21 or ofthe cover 35. In order to ensure an underflow 42 between the flap 23 andthe shaft 7 or the damming structure 30, provision is made here of anintegrated closure 43. This integrated closure 43 is a pivotable part inthe bottom region of the flap 23. The overflow 41 and also the underflow42 are direct hydraulic connections from the headwater 2 to thetailwater 6, bypassing the shaft 7 and also bypassing the electricitygenerating unit 15.

FIGS. 11 and 12 show a second variant of the flap 23. In FIG. 11, theflap 23 is shown in the closed state, wherein here, in turn, the topedge of the flap 23 is offset downward slightly with respect to theheadwater level 3, so that a constant overflow 41 is produced. In thissecond variant, no integrated closure 43 is provided. Instead of this,the flap 23 is mounted here such that its middle can be pivoted about ahorizontal pin 44. By pivoting the flap 23 out, the volume flow in theoverflow 41 and in the underflow 42 is simultaneously increased.

On account of the constant overflow 41, eddy formation above the shaft 7is avoided. Thus, flotsam can always be flushed on the surface of thewater from the headwater 2 to the tailwater 6, bypassing the electricitygenerating unit 15. On account of the underflow 22, which is controlledin a time-based or need-based manner, bed-load which is carried alongand has collected at the protrusion 33 or in the flushing channel 37 isremoved directly from the headwater 2 into the tailwater 6, bypassingthe electricity generating unit 15. In addition, the underflow 42 servesas an eel through-passage or serves for the downstream migration of fishthat swim close to the surface.

According to the invention, in all of the exemplary embodiments, theflow always flows in from top to bottom through the shaft and leaves theshaft horizontally through the unit 15. The inlet plane to the shaft isalways under water and a minimum coverage should be ensured in orderthat no eddies that draw in air occur. The exemplary embodiments areused preferably at silted-up transverse structures. These arecharacterized not only by a difference in water level(headwater/tailwater) but also by the fact that heavy bed-load transporttakes place in the event of high water. Furthermore, high speeds occurhere with a low flow depth and high discharges, it being necessary forsaid high speeds to be decelerated to less than 1 m/s in the screenplane upstream of the turbine. In conventional plants, this can takeplace only by deepening the approximately vertical inflow into theturbines. However, such arrangements are problematic in operation, sincedeposition of bed-load occurs in the inward flow into the turbines,resulting in losses of efficiency and operational disruptions. Incontrast thereto, the invention proposed affords the possibility ofincreasing the shaft cross section as desired in a 2D horizontal planeand thus of lowering the speeds without problems to 0.5 m/s or less. Thesize of the shaft cross section thus becomes an additional manipulatedvariable which can be optimized without problems for example with regardto fish friendliness.

The concept proposed includes operationally friendly and durablesolutions to the problems of bed-load. Further, high water can bedischarged without problems. Preferably, the entire width of the courseof the river is flowed over, i.e. as a result of the power plantconstruction, there is no loss of capacity and on account of theunderwater arrangement, there is no water damage. Furthermore, use canbe made of existing, even historic, weirs, which for economic andlandmark preservation reasons should be modified as little as possible.In conventional bay-type power plants, the water has to be diverted outof the course of the river and returned thereto again. This causes largeencroachments, high costs, operational difficulties and the powerhouseis visible and acoustically perceptible. The invention proposed changesthe discharge path of the existing course of the river only a little.

Alternatively, the unit with the turbine can preferably also be arrangedfor water to pass through vertically (vertical arrangement of the unit).The invention is illustrated, taking account of both variants, thehorizontal and the vertical arrangement of the unit, as follows:

-   -   a. A shaft power plant (1) for generating electricity by energy        conversion of a discharge between a headwater (2) and a        tailwater (6), comprising        -   a vertical shaft (7), the top (10) of which forms an inflow            plane (11) which is parallel to the bed and extends below            the water level (3) of the headwater, wherein the shaft (7)            is open toward the top and is closed by a base (9) at its            bottom end,        -   a unit (15) composed of a turbine (16) and an electrical            machine (17), wherein the unit (15) is arranged entirely            under water in the shaft (7) and wherein the turbine (16) is            arranged for water to pass through vertically or            horizontally, and        -   an outflow (24), which is connected to the turbine (16),            represents a closed flow channel and leads through a            through-passage (28) in the shaft (7) to the tailwater (6),        -   wherein, with the water passing through the turbine (16)            vertically, in a horizontal plane of a turbine runner (19)            of the turbine (16), a first cross-sectional area of the            shaft (7) is much larger than a second cross-sectional area            taken up by the turbine runner (19), or        -   with the water passing through the turbine (16)            horizontally, a horizontal first cross-sectional area of the            shaft (7) is much larger than a vertical second            cross-sectional area taken up by the turbine runner (19).    -   b. The shaft power plant according to point a, characterized in        that the first cross-sectional area is at least 1.5 times, in        particular 5 times, in particular 10 times, in particular 30        times larger than the second cross-sectional area.    -   c. The shaft power plant according to one of the preceding        points, characterized in that, in the horizontal arrangement of        the unit (15), the first cross-sectional area is defined at the        level of a turbine axis (45) or at the level of the shaft top        (10).    -   d. The shaft power plant according to one of the preceding        points, characterized in that the shaft top (10) is arranged in        the bottom half, in particular in the bottom third, of a water        depth (5) of the headwater.    -   e. The shaft power plant according to one of the preceding        points, characterized in that the shaft (7) is open over its        entire top side.    -   f. The shaft power plant according to one of the preceding        points, characterized in that all of the side walls (8) of the        shaft (7) extend vertically, so that the first cross-sectional        area is constant over the entire shaft depth (34). The vertical        shaft walls can preferably be designed in a flow-favorable        manner and/or comprise flow-favorable guide elements.        Alternatively preferred is a shaft form which leads from the        rectangular inflow cross section having a flow-optimized wall,        e.g. spiral shaped and/or having a circular cross section, to        the turbine.    -   g. The shaft power plant according to one of the preceding        points, characterized in that the turbine (16), in particular        the turbine runner (19), is arranged below the bed plane (4) of        the headwater and/or is arranged in the bottom half, in        particular in the bottom third, of the shaft (7).    -   h. The shaft power plant according to one of the preceding        points, characterized in that the turbine axis of the turbine        runner (19) and an armature axis of the electrical machine (17)        are arranged coaxially with one another and vertically or        horizontally.    -   i. The shaft power plant according to one of the preceding        points, characterized in that the outflow (24) widens, in        particular continuously, directly after the turbine (16).    -   j. The shaft power plant according to one of the preceding        points, characterized by a damming structure (30) between the        headwater (2) and the tailwater (6).    -   k. The shaft power plant according to point j, characterized in        that the shaft (7) is configured with a polygonal or        semicircular cross section, wherein one longitudinal side of the        shaft (7) butts directly against the damming structure (30).    -   l. The shaft power plant according to either of points j and k,        characterized in that at least one flap (23) which is        permanently overflowed is arranged in the damming structure        (30).    -   m. The shaft power plant according to point I, characterized in        that the flap (23) is configured to enlarge the overflow (41)        and to open an underflow (42).    -   n. The shaft power plant according to either of points I and m,        characterized in that an integrated closure (43) for regulating        the underflow (42) is arranged on a bottom edge of the flap        (23).    -   o. The shaft power plant according to one of the preceding        points, characterized in that, in a vertical arrangement of the        unit (15), the outflow (24) is curved, in particular through        90°.    -   p. The shaft power plant according to one of the preceding        points, characterized in that the base (9) of the shaft (7) is        arranged below the bed plane (4) of the headwater (2).    -   q. The shaft power plant according to one of the preceding        points, characterized in that, in the vertical arrangement of        the unit (15), the outflow (24) comprises, in the following        order downstream of the turbine (16), a flaring cone (25), an        elbow and a suction pipe or a suction hose (27), and in that, in        the horizontal arrangement of the unit (15), the outflow (24)        comprises, in the following order downstream of the turbine        (16), a flaring cone (25) and a suction pipe or a suction hose        (27).    -   r. The shaft power plant according to one of the preceding        points, characterized in that, in the vertical arrangement of        the unit (15), the outflow (24) is arranged above the turbine        runner (19), so that during electricity generation the water        flows through the turbine runner (19) from bottom to top.    -   s. The shaft power plant according to point r, characterized in        that the outflow (24) extends through a side wall (8) of the        shaft (7) to the tailwater (6).    -   t. The shaft power plant according to one of the preceding        points, characterized in that, in the vertical arrangement of        the unit (15), the outflow (24) is arranged under the turbine        runner (19), so that during electricity generation the water        flows through the turbine runner (19) from top to bottom.    -   u. The shaft power plant according to one of the preceding        points, characterized in that, in the horizontal arrangement of        the unit (15), the unit (15) is mounted directly on a side wall        (8) of the shaft (7) and the outflow (24) extends through the        side wall (8) to the tailwater (6).    -   v. The shaft power plant according to one of the preceding        points, characterized in that, in the horizontal arrangement of        the unit (15), the outflow (24) is arranged to the side of the        turbine runner (19), so that during electricity generation the        water flows horizontally through the turbine runner (19).    -   w. The shaft power plant according to point t, characterized in        that, in the vertical arrangement of the unit (15), the outflow        (24) extends through the base (9) of the shaft (7) to the        tailwater (6).    -   x. The shaft power plant according to either of points t and w,        characterized in that, in the vertical arrangement of the unit        (15), the shaft (7) is configured to form a cavity underneath        the base (9), wherein the base (9) of the shaft (7) forms a        ceiling of the cavity and wherein the outflow (24) extends        through the ceiling, the cavity and a side wall of the cavity as        far as the tailwater (6).    -   y. The shaft power plant according to one of the preceding        points, characterized in that an inflow (29) into the shaft (7)        is provided with a horizontal screen plane (21), or a vertical        screen plane (21), in particular with a horizontal cover (35)        over the shaft (7).    -   z. The shaft power plant according to one of points p to y,        characterized in that a flushing channel (37), which is located        lower than the shaft top (10) and lower than the bed plane (4)        of the headwater (2), extends around the shaft (7), wherein the        flushing channel (37) leads to the flap (23) and the bottom edge        of the flap (23) is arranged at the level of the flushing        channel (37).    -   aa. The shaft power plant according to one of points a to o,        characterized in that the base (9) of the shaft (7) is arranged        above the bed plane (4) of the headwater (2).    -   bb. The shaft power plant according to point aa, characterized        in that the outflow (24) comprises a cylindrical throughflow of        constant cross section through the damming structure (30).    -   cc. A shaft power plant module for generating electricity by        energy conversion of a discharge between a headwater (2) and a        tailwater (6), comprising        -   a vertical shaft module (7), the shaft top (10) of which            forms an inflow plane (11) which is parallel to the bed and            is configured to extend below the water level (3) of the            headwater, wherein the shaft module (7) is open toward the            top and is closed by a base (9) at its bottom end,        -   a unit module (15) composed of a turbine (16) and an            electrical machine (17), wherein the unit module (15) is            configured to be arranged entirely under water in the shaft            module (7) and wherein the turbine (16) is configured to be            arranged for water to pass through vertically or            horizontally, and        -   an outflow module (24), which is connected to the turbine            (16), represents a closed flow channel and is configured to            lead through a through-passage (28) in the shaft module (7)            to the tailwater (6),        -   wherein, with the water passing through the turbine (16)            vertically, in a horizontal plane of a turbine runner (19)            of the turbine (16), a first cross-sectional area of the            shaft module (7) is much larger than a second            cross-sectional area taken up by the turbine runner (19), or        -   with the water passing through the turbine (16)            horizontally, a horizontal first cross-sectional area of the            shaft (7) is much larger than a vertical second            cross-sectional area taken up by the turbine runner (19).

1. A shaft power plant for generating electricity by energy conversionof a discharge between a headwater and a tailwater, comprising: avertical shaft, the top of which forms an inflow plane which is parallelto a bed and extends below a water level of the headwater, wherein theshaft is open toward the top and is closed by a base at its bottom end,a unit having a turbine and an electrical machine, wherein the unit isarranged entirely under water in the shaft and wherein the turbine isarranged for water to pass through horizontally, an outflow, which isconnected to the turbine, that represents a closed flow channel andleads through a through-passage in the shaft to the tailwater, and adamming structure between the headwater and the tailwater, wherein ahorizontal first cross-sectional area of the shaft is much larger than avertical second cross-sectional area taken up by the turbine runner,further wherein at least one flap that is permanently overflowed isarranged in the damming structure or on a side wall of the verticalshaft.
 2. The shaft power plant of claim 1, wherein the firstcross-sectional area is at least 1.5 times, in particular 5 times, inparticular 10 times, in particular 30 times larger than the secondcross-sectional area.
 3. The shaft power plant of claim 1, wherein thefirst cross-sectional area is defined at a level of a turbine axis or ata level of the shaft top.
 4. The shaft power plant of claim 1, whereinthe shaft top is arranged in a bottom half, in particular in a bottomthird, of a water depth of the headwater.
 5. (canceled)
 6. The shaftpower plant of claim 1, wherein the side wall extends vertically, sothat the first cross-sectional area is constant over an entire shaftdepth.
 7. (canceled)
 8. The shaft power plant of claim 1, wherein aturbine axis of the turbine runner and an armature axis of theelectrical machine are arranged coaxially with one another andhorizontally. 9-10. (canceled)
 11. The shaft power plant of claim 1,wherein the shaft is configured with a polygonal or semicircular crosssection, further wherein one longitudinal side of the shaft buttsdirectly against the damming structure.
 12. (canceled)
 13. The shaftpower plant of claim 1, wherein the flap is configured to enlarge anoverflow and to open an underflow.
 14. The shaft power plant of claim13, wherein an integrated closure for regulating the underflow isarranged on a bottom edge of the flap.
 15. The shaft power plant ofclaim 1, wherein the base of the shaft is arranged below a bed plane ofthe headwater.
 16. The shaft power plant of claim 1, wherein the outflowcomprises, in the following order downstream of the turbine, a flaringcone and at least one of a suction pipe and a suction hose.
 17. Theshaft power plant of claim 1, wherein the unit is mounted directly on aside wall of the shaft and the outflow extends through the side wall tothe tailwater.
 18. The shaft power plant of claim 1, wherein the outflowis arranged to a side of the turbine runner, so that during electricitygeneration the water flows horizontally through the turbine runner. 19.The shaft power plant of claim 1, wherein an inflow into the shaft isprovided with a horizontal screen plane.
 20. The shaft power plant ofclaim 15, wherein a flushing channel, which is located lower than theshaft top and lower than the bed plane of the headwater, extends aroundthe shaft, wherein the flushing channel leads to the flap and a bottomedge of the flap is arranged at a level of the flushing channel.
 21. Theshaft power plant of claim 1, wherein the base of the shaft is arrangedabove a bed plane of the headwater.
 22. The shaft power plant of claim21, wherein the outflow comprises a cylindrical throughflow of constantcross section through the damming structure.
 23. A shaft power plantmodule for generating electricity by energy conversion of a dischargebetween a headwater and a tailwater, comprising: a vertical shaft modulehaving a shaft top that forms an inflow plane which is parallel to a bedand is configured to extend below a water level of the headwater,wherein the shaft module is open toward the top and is closed by a baseat its bottom end, a unit module having a turbine and an electricalmachine, wherein the unit module is configured to be arranged entirelyunder water in the shaft module and wherein the turbine is configured tobe arranged for water to pass through horizontally, and an outflowmodule, which is connected to the turbine, that represents a closed flowchannel and is configured to lead through a through-passage in the shaftmodule to the tailwater, wherein the shaft power plant module isconfigured to be attached to a damming structure between the headwaterand the tailwater, further wherein a horizontal first cross-sectionalarea of the shaft module is much larger than a vertical secondcross-sectional area taken up by the turbine runner, and further whereinat least one flap that is permanently overflowed is arranged in thedamming structure or on a side wall of the vertical shaft.
 24. The shaftpower plant of claim 1, wherein a bottom edge of the flap is arranged ata level of the shaft top, in particular at a level of a screen plane.25. The shaft power plant of claim 1, wherein the flap, as seen in aviewing direction from the headwater to the tailwater, is arrangeddirectly downstream of the vertical shaft.